Otolemur garnettii

Geographic Range

Otolemur garnettii is also known as the small-eared galago or Garnett’s greater galago. This species is found in East Africa, ranging from the southern half of Somalia to Tanzania (Bearder et al., 2003) and on the island of Zanzibar (Groves, 2001).

• Biogeographic Regions
• ethiopian ethiopian
  • native native

Habitat

Middle to high canopies in coastal, riverine, and highland forests form the natural habitat for small-eared galagos. They are also found in farmland plantations.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest
• scrub forest scrub forest

• Other Habitat Features
• agricultural agricultural

Physical Description

Otolemur garnettii are relatively small members of the genus Otolemur , with short ears. They were once considered subspecies of Otolemur crassicaudatus . Average ear length is 45 mm compared to the larger ear length of 62 mm in O. crassicaudatus (Rowe, 1996).

Small-eared galago males are only slightly larger than females. Adult males weigh an average of 794 grams, females weigh 734 grams (Fleagle, 1999). Otolemur garnettii has a thick and bushy tail that is longer than its entire body. Total body length averages 266 mm and tail length averages 364 mm (Rowe, 1996).

Small-eared galagos can be recognized by the red to gray-brown color of their pelage and by the presence of a brown, white, or black tip on their tail (Rowe, 1996). Their faces are uniformly colored (Groves, 2001). There are four subspecies of small-eared galagos that can be distinguished by the coloration of their fur (Groves, 2001). Otolemur garnettii garnettii has slightly greenish tones in its red-brown fur, the yellow color of its underside, and the presence of black tip on the last half of its tail. Otolemur garnettii panganiensis lacks green tones in its pelage and only possesses a black tip on the last quarter of its tail. Otolemur garnettii lasiotis is more gray than O. g. garnettii and tends to have a white-tipped tail. Otolemur garnettii kikuyuensis is characterized by its yellow-white underside, an iron gray pelage, and a black tip on the last quarter of its tail (Groves, 2001).

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry
• polymorphic polymorphic

• Sexual Dimorphism
• male larger

Reproduction

The O. garnettii mating system is usually described as promiscuous, as both males and females have multiple mates. The act of mating in this species can take up to 120 minutes. It has been suggested that the extremely long duration of mating in this species is one way that males guard females from other males (Rowe, 1996).

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

In the wild, O. garnettii has been observed breeding seasonally once each year between August and October (Nash and Harcourt, 1986). Captive populations can give birth throughout the year, which indicates that females have a continuous estrus cycle (Masters et al., 1988). Females usually give birth to one infant and members of both sexes reach sexual maturity when they are about 20 months old (Nash and Harcourt, 1986). Weaning occurs after approximately 140 days (Rowe, 1996).

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous

Parental investment seems to be provided only by mothers. They carry infants in their mouths but leave them while foraging (Rowe, 1996). Before weaning, mothers provide offspring with high-energy milk and protect them from predators and other dangers.

• Parental Investment
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • provisioning
    • female

Lifespan/Longevity

Small-eared galagos can live for up to 15 years (Bearder, 1987).

Behavior

Small-eared galagos are nocturnal and arboreal. It is uncommon to observe small-eared galagos on the ground. Both males and females have home ranges that do not overlap with individuals of the same sex or age (Nash and Harcourt, 1986). Compared to females, males disperse further from the area in which they were born and do so at an earlier age. Males are transient members of groups and usually remain solitary forgers (Rowe, 1996). Females mature and remain in their natal areas, but same-aged females do not share overlapping ranges. Related females are usually the only individuals that share a common home range. This may be explained by the fact that O. garnettii rely on fruit as a significant part of their diet. During different times of the year, the abundance and quality of fruit can vary considerably between forest patches. Thus, O. garnettii may be under pressure to exclude unrelated individuals from important areas of forest that contain variable and limited food resources.

Grooming and play occurs in O. garnettii between individuals of both sexes. Small-eared galagos run and climb on four feet, but also engage in bipedal hopping by jumping and landing on the hind limbs first (Nash and Harcourt, 1986). They usually sleep in vine tangles. Males sleep alone while females sleep with offspring (Rowe, 1996).

• Key Behaviors
• arboreal arboreal
• scansorial
• nocturnal nocturnal
• motile motile
• sedentary sedentary
• solitary solitary
• territorial territorial

Home Range

Female home ranges are approximately 11.6 ha, male home ranges are approximately 17.9 ha.

Communication and Perception

Members of both sexes frequently use vocal communication. Vocalizations can even be used to distinguish between the individuals of this species. Their most notable call may be heard from 400 feet away and lasts for 4 to 5 seconds, longer than the calls of O. crassicaudatus (Rowe, 1996). Researchers have been able to group different calls based on their function and have observed alarm calls, sex calls, distress calls in response to fear, and infant click calls that elicit contact from the mother. Foot-rubbing may even be used for communication. Individuals rub their feet against another material and vary the intensity of the sound they produce. This behavior produces a sound that is not different from background noise, so foot-rubbing may allow small-eared galagos to communicate with conspecifics without alerting predators (Hagar, 2001). Small-eared galago males have been observed using foot-rubbing during aggressive encounters with other males.

Other forms of communication include the use olfactory signals. Otolemur garnettii has been observed to engage in urine washing, which it accomplishes by urinating on its hands and then rubbing the urine on the bottom of its feet. This behavior allows galagos to leave their scent on everything they touch. Males seem to engage in urine washing more often than females (Tandy, 1976). In addition to marking their scent on objects, individuals can communicate by sniffing one another.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

• Other Communication Modes
• pheromones pheromones
• scent marks scent marks

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Small-eared galagos primarily feed on fruit and insects. About half of their diet is composed of fruit and half is composed of insects (Nash and Harcourt, 1986).

• Primary Diet
• omnivore omnivore

• Animal Foods
• insects

• Plant Foods
• fruit

Predation

The most likely predators of small-eared galagos are genets ( Genetta tigrina ) and puff adders ( Vipera berus ) (Nash, 1983).

Ecosystem Roles

Small-eared galagos may have an important ecological role in the forests of East Africa because they eat fruit and insects. They may serve as seed dispersers for a variety of plant species, thus influencing the plant composition of the ecosystem.

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

Otolemur garnettii individuals are important members of the ecosystems in which they live and they may help in ecotourism ventures.

• Positive Impacts
• ecotourism ecotourism

Economic Importance for Humans: Negative

Small-eared galagos have no negative economic impact on humans.

Conservation Status

Small-eared galagos are labeled as “lower risk” on the IUCN redlist and on Appendix II of CITES to limit international trade of this species.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Randa Tao (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor.

References

Bearder, S., L. Ambrose, C. Harcourt, P. Honess, A. Perkin, E. Pimley, S. Pullen, N. Svoboda. 2003. Species-Typical Patterns of Infant Contact, Sleeping Site Use and Social Cohesion among Nocturnal Primates. Folia Primatologica , 74: 337-354.

Bearder, S. 1987. Lorises, Bushbabies, and Tarsiers: Diverse Societies in Solitary Foragers. Pp. 11-24 in Primate Societies . Chicago: University of Chicago Press.

Fleagle, J. 1999. Primate Adaptation and Evolution . San Diego: Academic Press.

Groves, C. 2001. Primate Taxonomy . Washington, D.C.: Smithsonian Institution.

Hager, R. 2001. Foot-rubbing as a multifunctional form of intraspecific communication in Garnett's greater bushbabies (Otolemur garnettii). Folia Primatologica , 72: 104-107.

Masters, J., W. Lumsden, D. Young. 1988. Reproductive and dietary parameters in wild greater galago populations. International Journal of Primatology , 9: 573-592.

Nash, L. 1983. Reproductive patterns in galagos (Galago zanzibaricus and Galago garnettii) in relation to climatic variability. American Journal of Primatology , 5: 181-196.

Nash, L., C. Harcourt. 1986. Social Organization of Galagos in Kenyan Coastal Forests:II. Galago garnettii. American Journal of Primatology , 10: 357-369.

Price, M., M. Becker, J. Ward. 1999. Play behavior in infant small-eared bushbabies (Otolemur garnettii). (Abstract). American Journal of Primatology , 49: 88-89.

Rowe, N. 1996. The Pictorial Guide to the Living Primates . New York: Pogonias Press.

Tandy, J. 1976. Communication in Galago crassicaudatus. Primates , 17: 513-526.

Whitehead, P., W. Saaco, S. Hochgraf. 2005. A Photographic Atlas for Physical Anthropology . Englewood, Colorado: Morton Publishing Company.